Field of the Invention
This invention relates to systems and methods for copying data, and more specifically to systems and methods for selecting an optimal copy algorithm to copy data.
Background of the Invention
Over time and with improvements in hardware and other technology, data copy algorithms are improved to be faster and more efficient. IBM's System Data Mover (SDM) currently can implement both the “Concurrent Copy” and “FlashCopy” point-in-time copy algorithms, each of which was developed at different times. Concurrent Copy is the oldest and slowest method of copying data but is versatile since the source and target volumes can be on different LSS hardware configurations. Concurrent Copy also requires a certain amount of auxiliary storage to operate properly. This auxiliary storage is used to store a “sidefile” that maintains a copy of changed tracks that have yet to be copied. FlashCopy, by contrast, is the most recent and fastest method of copying data. FlashCopy provides a point-in-time copy of a volume with almost instant availability for the user of both the source and target volumes. However, for FlashCopy to be used, the source and target volumes must both reside in the same LSS hardware configuration.
In certain cases, users may experience sub-optimal efficiency because they are using older copy algorithms that were the only options available at the time batch jobs were created for copying data. For example, large numbers of batch jobs were created using the oldest Concurrent Copy algorithm. Today these jobs are still frequently used even though the FlashCopy algorithm is available. This is at least partly because converting the jobs to use newer and more efficient copy algorithms requires significant labor costs associated with hardware reviews and hours of Job Control Language (JCL) conversions.
In view of the foregoing, what are needed are systems and methods to enable use of the most efficient copy algorithms available for particular hardware configurations. Ideally, such systems and methods will enable the copy algorithms to be used without requiring changes or updates to batch jobs or other executable code using older and less efficient copy algorithms.